Many people are now converting to other religions because they see that vedic Hinduism does not teach Truths. While others are simply too confuse with many Gods within One religion term as Hinduism. And caste system exist within vedic teachings hence the essence of
Hinduism is slowly dying out.

Your thread of  "That Nepal will always be a Hindu Nation" will only succeed if Nepal goes back to be followers of Original Hindu Religion and Practices which can be label as Kirat Hindusim.
Origin religion of Hinduism is religion of native tribes.
In another word, the ideology is that Nepal must go back to be followers of Kirat Hinduism and
not be Vedic Hindu followers.
Kirat Hindusim is casteless, simple and basically is of nature worshiping in which Paruhang(Siva)
and Summina(Uma) are considered Lord of Kiratas.
I have highlighted some evident and reasons from ancient texts (Vedic literature) and through scholars, foreign as well as Indian/Nepali that religion of Hindu and practices existed long before the Rig-Veda(the oldest Indian text) was constructed in the thread call "The Origin of Hindu Religion"

Link
 http://www.sajha.com/sajha/html/OpenThread.cfm?forum=2&ThreadID=71141

If Nepal is to follow Kirat Hinduism instead of Vedic Hinduism, it brings two essence.

1. Reviving the religion of native tribes.
2. the glory of the caste less Nepal again.

This no doubt surely answer your call to "That Nepal will always be a Hindu Nation" but different from
Indian influence vedic Hinduism and hence preserving national identity.